I own a paintball business and I just ordered an eNMEy to try it out (got it today). I also recently ordered 10 FT-12's to try out (in October). I fired the eNMEy and an FT-12 and I was thinking about ordering 10 more of the eNMEy. Unfortunately, when I went to take them apart side by side there was a problem with the eNMEy. It was the wierdest thing; a screw in the ASA was stuck (I got it to move, but turning it farther will shear the screw). I emailed my GOG rep tonight about it, but I am a little turned off by this. I think I'm going to have 10 of each of those markers for the spring to let groups try out so that I can get some feedback and determine which one I will replace my rentals with (I already started getting rid of my T98 rentals).
DIRECT COMPAIRISON: eNMEy is lighter, eNMEy anti chop is better (you have to re-cock the FT-12 but not the eNMEy), the people that I rented the FT-12's out to in the fall thought it looked like a uzi, so I am going with FT-12 is more visually appealing (I expect some will dissagree, but I will see in the spring with my customers), the eNMEy is a little quieter, but it is not a big difference (draw), firing rate is slightly in favor of eNMEy in my hand, but in a younger (weaker) persons hand it may be more of a difference, cleaning time is better on the eNMEy. I am not sure about long term durability, but I expect that Tippmann will win that one in a big way, but the warranty for the GOG marker will help with that (I don't think it applies to commercial/rental ones though). I should mention that not having to repair a marker in the first place is way better than getting a free replacement part! Also, there are some accessory options for the eNMEy, which I haven't seen for the FT-12 yet (perhaps later???). I think the eNMEy will be more consistant over the chrono, but I haven't tried yet. Chrono consistancy is a big contributer to accuracy (chrono (velocity) variation will cause mid to long range shots to over-shoot or under-shoot), so if the eNMEy performs like I think it will (like the eNVy or eXTCy, which appear to have the same regulator) it will be more accurate than the FT-12.
I will give an update in the spring. I might also put out a video. (Stew's Paintball)

We have 20 in our rental fleet at the moment, and we are having issues with the 3way leaking in almost all of them. Gog informed me that they are aware of the problem and have sent me the replacement parts. Supposedly they have made some minor changes to the 3way. Honestly I can not see a difference, but the new parts work and I have yet to have a problem with the new parts leaking. (however it has only been 2 weeks, so we will see).

On a side note, there is a very small leak somewhere in all of the guns because on Saturday morning (after being left aired up during the week) all of the air tanks are empty.

We have 20 in our rental fleet at the moment, and we are having issues with the 3way leaking in almost all of them. Gog informed me that they are aware of the problem and have sent me the replacement parts. Supposedly they have made some minor changes to the 3way. Honestly I can not see a difference, but the new parts work and I have yet to have a problem with the new parts leaking. (however it has only been 2 weeks, so we will see).

On a side note, there is a very small leak somewhere in all of the guns because on Saturday morning (after being left aired up during the week) all of the air tanks are empty.

Hmmmm....you may consider degassing them. The constant strain on internal air lines sounds like the factor causing your leak. BB's don't mind being gassed constantly but I can't see the Enmeys internals being as able to tolerate the constant pressure.

I don't really think there is much of a comparison between Tippy BBs and the GOG marker though, its the only modern mech marker being used for rental use that I would consider worth owning personally.

I tech for our local field and they have 40 GOG ENMEYS as rentals. So far there have been some re-occurring issues:

- Solenoid leaks
The solenoid housing is made from plastic and often the little disc that sits in the heart of it gets misaligned causing a leak probably due to some debris that might get into the marker. The housing itself is not very durable and needs some care during reassembling, making sure not to over tighten the 2 screws holding it as this might result in some misalignment or stripped grooves and preventing the housing from being air-tight. I feel that this is a serious oversight by GOG and have emailed them about maybe upgrading the overall solenoid to have an aluminium/metal body instead for the RENTAL version for obvious reasons. To test how sensitive this setup was we aired the marker up while leaving the solenoid exposed and just by pressing the solenoid housing between your fingers, you could misalign the seal and cause a leak. We also experienced some leaks where the 3 hoses connect to the solenoid body and on one, we had to cut the hose shorter in order to make the connection more flush to eliminate the air leak.

- Feedneck
The feedneck is also made out of plastic, although they were smart to have a nut and screw setup, at some instances, if the screw was overtightened or misaligned, when opening the screw, the nut would rotate together with the screw causing to strip the feedneck body where it holds the nut in place as the plastic is very bendable. A replacement clamping feedneck is recommended here or a metal feedneck should be included standard in the RENTAL version

- Safety pin
The safety pin setup is not durable at all. If overpushed either way (which we have no control over with customers) the pin would fall out and along with a very tiny ball bearing and spring setup, once lost these are impossible to find. This could have easily been fixed during the design stage by adding a c-clip around the safety pin inside of the marker body. I do not foresee this part ever having to be replaced if the safety pin was made out of metal. Again this should be in applied in the RENTAL version.

- ASA
The ASA setup is not an on/off which we expect for a rental marker but it also employs the same nut and screw setup as the feedneck to attached to the marker grip. I foresee having to deal with this problem in the future as well.

Of the 40 markers we have, 2 are severely down due to lost safety pins, 1 stripped feedneck and broken solenoids. We have worked them now for less than 1 month.

Although the above will happen to the markers eventually (sooner for most) GOG has been very responsive to send replacement parts for free (but you must pay for shipping) and stick true to their LIFETIME WARRANTY agreement. But as somebody mentioned earlier it would have been better to not have the problem in the first place rather than to have to ask for free parts to fix them.